Allan Guan
ECE 3130 – Digital Electronics and Design
Lab 1Introduction to Tanner Tools
Fall 2012
Allan Guan
Objectives
• Review basic digital circuit concepts• Develop an understanding of digital circuit
design and simulation• Learn the basics of the Tanner Tools software
Allan Guan
How do digital circuits work?
• Analog – continuous signal• Digital – discrete signal• Fundamentally binary devices• Quantization of voltage– HIGH– LOW
Allan Guan
Generic Voltage Transfer Characteristics
• Input– IN ≤ VIL “0”– IN ≥ VIH “1”
• Output– OUT ≤ VOL “0”– OUT ≥ VOH “1”
Allan Guan
Propagation Delay (tP)• When the gate inputs change, the
outputs do not change instantaneously
• Defined as the latency between a change in the input and a change in the output measured from the 50% point at the input and the 50% point at the output
• tPHL – the time it takes for the output to switch from HIGH to LOW
• tPLH – the time it takes for the output to switch from LOW to HIGH
Allan Guan
Logic Gates
• AND• OR• NOT (a.k.a. inverter)• NAND• NOR• XOR• XNOR
Allan Guan
Introduction to MOSFETS
• Four terminal devices– Gate– Source– Drain– Body
• Two types– PMOS – source connected to VHIGH
– NMOS – source connected to VLOW
• *NOTE*: The body is always shorted to the source in both devices
Allan Guan
Tanner Tools Components
• 5 Modules– L-Edit– LVS– S-Edit– T-Spice– W-Edit
Allan Guan
Let’s Start…
• Start All Programs Tanner EDA Tanner Tools v15.0 S-Edit v15.0 64-bit
Allan Guan
This is the startup interface
Allan Guan
Make a new design file
Allan Guan
• Name the design• Create a directory to store your files and set the path
Allan Guan
Make a new cell
Allan Guan
Name the cell and select schematic
Allan Guan
This is the schematic workspace
Allan Guan
Add the following libraries:• C:\Users\Student\Documents\Tanner EDA\Tanner Tools v15.0\Process\Generic_250nm\
Generic_250nm_Devices\Generic_250nm_Devices.tanner• C:\Users\Student\Documents\Tanner EDA\Tanner Tools v15.0\Process\Standard_Libraries\
Misc\Misc.tanner
Allan Guan
Inverter
• Truth table
• Implementation
Input Output
0 1
1 0
Allan Guan
Select the devices library
Select the desire component from the parts list
Press “Instance”
Allan Guan
Left-click to place on grid then click DoneSelect 4T
Allan Guan
Vdd and Gnd are found in the Misc library
Wire In Out
Allan Guan
Now let’s make a symbol for the inverter
Allan Guan
• Select the same cell as your schematic• Select “symbol” from view• Click OK
Allan Guan
This is the symbol workspace.Let’s have Tanner generate a symbol for us.
Allan Guan
Make sure the Design and Cell are correct and then hit “Replace”
Allan Guan
• This is the auto-generated symbol but let’s make it better.• Pick the Pointer tool, select the box, and press Backspace to
delete it
Pointer
Allan Guan
• Pick the “Path” tool and “All angle” selection • Draw the standard logic symbol for an inverter• Draw “paths” to connect everything
All anglePath
Allan Guan
Building the Test Bench
• Make new design file• Call it inverter_test• Add the inverter library, which you just made• Add the following libraries– C:\Users\Student\Documents\Tanner EDA\Tanner Tools
v15.0\Process\Standard_Libraries\SPICE_Commands\SPICE_Commands.tanner
– C:\Users\Student\Documents\Tanner EDA\Tanner Tools v15.0\Process\Standard_Libraries\SPICE_Elements\SPICE_Elements.tanner
Allan Guan
• Voltage source is found in the SPICE_Elements library• Print Voltage is found in the SPICE_Commands library• Capacitor is found in the Devices library
Voltage source (pulse)
Allan Guan
C:\Users\Student\Documents\Tanner EDA\Tanner Tools v15.0\Process\Generic_250nm\Generic_250nm_Tech\Generic_250nm.lib TTPress this button
to set up the simulation
Allan Guan
Set the stop time and maximum time step and hit Run Simulation
Allan Guan
Allan Guan
NAND Gate
• Truth table
• Implementation
A B Output
0 0 1
0 1 1
1 0 1
1 1 0
Allan Guan
Allan Guan
Allan Guan
Allan Guan
Analysis
• Tabulate the propagation delays (tPHL, tPLH) for the inverter and NAND gate.
• Record the waveforms.